Coffee chain Starbucks announced last week that it is trialling the introduction a 5p charge for takeaway cups. The proceeds will be donated to environmental charity Hubbub. Starbucks is the first UK coffee chain to make such a move and it hopes that the charge will reduce the use of disposable cups.

Perhaps unwittingly, Starbucks appears to have based its trial on important insights from behavioural economics and this may significantly increase the likelihood that it is successful.

Behavioural economics was thrown into the spotlight last year when one of its leading advocates, Richard Thaler, was awarded the Nobel prize in Economics. However, two of Thaler’s mentors, Amos Tversky and Daniel Kahneman, sowed the seeds for the field of behavioural economics. Most notably, in one of the most cited papers in economics, in 1979 they published a ground breaking alternative to the standard model of consumer choice.

One of the key insights from their model, known as prospect theory, is that rather than simply being concerned with their overall level of wealth, individuals care about gains and losses in wealth relative to a reference point. Furthermore, individuals are loss averse – a loss hurts about twice as much as an equivalent gain makes them feel good.

So how does this help to predict how consumers will react to Starbucks’ trial? Well, crucially, Starbucks is increasing the price of coffee in a takeaway cup. Prospect theory predicts that consumers will see this as a loss relative to the pre-trial price, which serves as a reference point. Since this hurts them a lot, they will be likely to take measures to avoid the levy. In support of this, research undertaken by Starbucks shows that 48% of consumers asked said that they would definitely carry a reusable cup to avoid paying the extra 5p.

As the company’s vice-president of communications, Simon Redfern, made clear, this would be in stark contrast to Starbucks’ previous attempts to reduce waste:

We’ve offered a reusable cup discount for 20 years, with only 1.8% of customers currently taking up this offer.

Furthermore, in 2016 they even experimented with increasing the discount from 25p to 50p. However, the impact on consumer behaviour remained low. Again, this evidence is entirely consistent with prospect theory. If consumers view the discounted price as a gain relative to their reference point, while they would feel some benefit from saving money, this would be felt much less than the equivalent loss would be.

Therefore, it seems likely that introducing a charge for takeaway cups will prove a much better way to reduce waste. More generally, this example demonstrates that the significant insights which prospect and other behavioural theories provide should be taken into account when trying to intervene to influence consumer behaviour in markets.

Each year for the past 60 years, the ONS has published ‘Family Spending’, which ‘gives an insight into the spending habits of UK households, broken down by household characteristics and types of spending’. The latest issue, covering the financial year ending 2017, has just been released.

To mark the 60th anniversary, the ONS has also published a blog, Celebrating 60 years of Family Spending, which compares spending patterns in 2017 with those in 1957. The blog looks at the percentage of the family budget spent on various categories, such as food, clothing, housing, tobacco and alcohol. Some of the percentages have changed dramatically over the years; others have hardly changed at all.

Before you read on, of the six categories mentioned above, which do you think have increased, which fallen and which stayed the same? What is your reasoning?

Differences in patterns of consumption partly reflect incomes. In 1957, real household income was £381 in today’s prices; today it’s £544 (43% more). You would expect, therefore, that a greater proportion of household incomes today would be spent on more luxurious goods, with a higher income elasticity of demand.

Other changes in consumption patterns reflect changes in tastes and attitudes. Thus there has been a huge fall in the proportion of household income spent on tobacco – down from 6% in 1957 to 1% in 2017.

Three of the biggest changes over the 60 years have been in housing costs, food and clothing. Housing costs (rent, mortgage interest, council tax, maintenance and home repairs) have doubled from around 9% to around 18% (although they were around 20% before the huge fall in interest rates following the financial crisis of 2007–8). Expenditure on food, by contrast, has fallen – from around 33% to around 16%. Expenditure on clothing has also fallen, from around 10% to around 5%.

Expenditure on alcohol, on the other hand, having risen somewhat in the 1970s and 80s, is roughly the same today as it was 60 years ago, at around 3% of household expenditure.

Some of the explanations for these changing patterns can be found on the supply side – changing costs of production, new technologies and competition; others can be found on the demand side – changes in tastes and changes in incomes. Some goods and services which we use today, such as computers, mobile phones, many other electrical goods, high-tech gyms and social media were simply not available 60 years ago.

We are coming into the big spending season, with Black Friday, Cyber Monday, the run-up to Christmas and then the winter sales. So will we all be rational maximisers and weigh up the utility we expect to receive from items against the price we pay (plus any other cost, such as time spent searching/shopping)? Or will we use a set of heuristics which make life easier and that we have found to be useful in helping us choose – heuristics such as buying things we’ve liked before, or going for things on special offer?

The answer is that we do probably use a set of heuristics, at least for many items. And don’t the retailers and the marketing firms they employ know this!

They will use all sorts of tricks of the trade to persuade us to part with our money. These tricks are designed to nudge us (or push us), without us feeling manipulated or conned – at least until we’ve bought their product.

And the tricks are getting more sophisticated. They include special offers which are not as good as they seem, time-limited offers which stimulate us to buy quickly without carefully thinking about what we’re doing, cunning positioning of products in shops to encourage us to buy things we had not planned to buy, adverts which play to our idealised perceptions or the ‘good life’ or what we would like to achieve, and packaging or display which make the product seem better than it is.

Also we are increasingly faced with targeted advertising where our smart devices capture information about our spending habits and tastes through our previous online spending or our search behaviour. This is then fed to advertisers to tailor adverts specifically to us on our mobiles, tablets, laptops and even, soon, on our smart TVs.

We may have a general desire to maximise utility from our spending, but market failures, such as consumers having imperfect information about products and a present bias (see also) in decision making, make us easy targets for the advertising and marketing industry. They understand the heuristics we use and try to take maximum advantage of them.

Richard H. Thaler has incorporated psychologically realistic assumptions into analyses of economic decision-making. By exploring the consequences of limited rationality, social preferences, and lack of self-control, he has shown how these human traits systematically affect individual decisions as well as market outcomes.

In total, Richard Thaler’s contributions have built a bridge between the economic and psychological analyses of individual decision-making. His empirical findings and theoretical insights have been instrumental in creating the new and rapidly expanding field of behavioural economics, which has had a profound impact on many areas of economic research and policy.

Instead of making the assumption that people are rational maximisers, behavioural economists look at how people actually behave and respond to various incentives.

For example, people may be motivated by concepts of fairness and be prepared to make personal sacrifices for the sake of others. Such concepts of fairness tend to depend on the social context in which choices are made and can be influenced by the way choices are framed.

Also people may not weigh up costs and benefits but use simple rules of thumb, or heuristics, when making decisions. This might be an example of rational behaviour when time or information is limited, but the use of such heuristics often becomes engrained in behaviour and the rules become just habit.

People may also suffer from a lack of willpower or ‘present bias’. They may spend more than they can afford because they cannot resist the temptation to have a product. They may overeat because of the short-term pleasure it brings and ignore the long-term effects on their health.

Understanding how people make choices and the temptations to which they succumb can help policymakers devise incentives to change behaviour to achieve various social goals.

One type of incentive is nudging. A well-known example is people’s choice about whether to become an organ donor in the event of their death. If people are required to opt in to such a scheme, they may never get round to doing so. However, if they are required to opt out if they do not want to participate, many more people would thereby be donors and more organs would become available.

Another form of nudge is making desirable things fun. A well-known experiment here was encouraging people to use the stairs rather than the escalator when exiting a subway by making the stairs like a musical keyboard. See here for more examples.

The UK government set up a Behavioural Insights Team – also known as the Nudge Unit (now independent of government) to find ways of encouraging people to behave in their own or society’s best interests.

But it is not just governments which use the insights of behavioural economists such as Thaler. The advertising and marketing industry is always examining the most effective means of influencing behaviour. A classic example is the loss leader, where consumers are tempted into a shop with a special offer and then end up buying more expensive items there rather than elsewhere.

Firms and advertisers know only too well the gains from tempting people to buy items that give them short-term gratification – such as putting chocolate bars by the tills in supermarkets.

Understanding consumer psychology helps firms to manipulate people’s choices. And such manipulation may not be in our best interests. If we are being persuaded to buy this product or that, are we fully aware of what’s going on and how our tastes are being affected? Would we, by standing back and reflecting, make the same choices as we do on impulse or out of habit?

And governments too can seek to manipulate people in ways that some may find undesirable. Governments may try to influence us to follow their particular political agenda – as may newspapers. Certainly, during election or referendum campaigns, we are being nudged to vote a particular way.

It is important then for us to understand when we are being nudged or otherwise persuaded. Do we really want to behave in that way? Just as it is important, then, for governments and firms to understand individuals’ behaviour, so too it is important for individuals to understand their own behaviour.

An oft-repeated quote is that money can’t buy happiness. But according to multiple studies, yes, it can. The key is what you spend that hard earned cash on. When researchers asked individuals to reflect on their recent purchases, those who had made experiential purchases i.e. trips, lessons, events, etc. were much happier compared to those who had made material purchases.

Why is this the case? According to a 20 year study at Cornell, our excitement from new purchases fades quickly over time. That new watch you bought quickly becomes a part of your everyday life. This is what psychologists call the “hedonic treadmill,” which describes the way we return to our normal state of happiness after a momentous occasion. However, buying a new chair will return you much quicker to that state than an adventure across the Rocky Mountains.

Researchers identified several key reasons why this is the case. One reason is that an object is just an object and can never become a part of your identity (at least, not a healthy one), whereas experiences shape us over time. In addition, because by definition unique experiences are only short-lived, we don’t adapt to them the way we might with a new phone or watch. They do not become part of the routine and as such are usually viewed in a special light.

Interestingly, researchers found that even a negative experience could be rated more highly than purchasing a luxury good. In the study, participants were asked to describe a bad experience they had recently and a few weeks later, they were asked again about it. Over the course of just a few weeks, most people’s opinion of that moment had changed.

This is because the human brain has a tendency to reduce the impact of stressful situations. In fact, a significant portion of those polled even stated that in the end, they were happy to have had the negative encounter as it gave them a fresh way to look at things. When similar questions were asked to those who had purchased a high-end item, their levels of happiness were consistently lower as time went on.

So when it comes to the age old question of “Does money buy happiness?” the answer is a resounding yes – provided you spend it on the right things. But of course, you should still aim to make every dollar go as far as possible in pursuit of great experiences. Take a look at the infographic below to see a visual summary of the research on money and how it can buy happiness.